I've found a very odd issue I'm haivng with Office 365 Rooms. When I try to book a meeting with no end time. The Room will book the meeting, but after 26 weekly entries the meeting is disappaers from the Room's calander but will remain in mine.

I also tried doing the same though OWA on my account, and again after 26 entries they do not show, but this time for both the Room's calandar and my own calandar.

I've attached an image, both entries have had no end date set but are showing diffrent end days.